1. Field of the Invention
The present invention relates to communications over power lines, and more specifically to circuits and systems for use in high temperature environments for demodulating data signals transmitted over power lines and transmitting modulated data signals over power lines.
2. Description of Related Art
Environments in which it would be desirable to operate sensors and actuators that employ semiconductor electronics can have ambient temperatures that are too high for the electronics to properly operate. For example, high temperatures are generated by metal smelting or sintering processes, steel production, down hole deep drilling, and vehicle engine operation, such as aircraft engine operation. The electronic components in conventional sensors and actuators may not operate properly under the high temperature conditions generated by such processes.
Further, environments in which it would be desirable to operate sensors and actuators that employ semiconductor electronics can experience ionizing radiation levels that are too high for the electronics to properly operate. The electronic components may experience so called latch-up when operated in such environments. Environments having high ionizing radiation levels include outer space, for example Earth orbital environments, and various planetary surfaces.
Conventional sensors and actuators typically require separate power supply and data conductors. Extra conductors can increase system weight, cost, required space, and the risk of equipment failure. It would be desirable to provide a circuit for a sensor or actuator that employs a common power and data conductor and which is able to withstand high ambient temperature conditions or high ionizing radiation levels.